There has conventionally been known a fluid transport device embodied as a uniaxial eccentric screw pump. The uniaxial eccentric screw pump includes a stator having a tubular shape and provided with a through hole in a female screw shape, and a rotor having a male screw shape, inserted through the through hole of the stator to form a transport space between the rotor and an inner circumferential surface of the through hole, and configured to rotate to shift the transport space from an inlet port side to a discharge port side. The through hole of the stator has interference formed by an elastic deformation thereof due to the rotor being pressed to the stator, and the interference is smaller on the discharge port side than on the inlet port side (see JP 5388187 B1, for example).
The conventional fluid transport device may have the following problem in a case where fluid is highly volatile or contains a large amount of dissolved gas. In a case where the transport space is larger on a downstream side than on an upstream side in a transport direction due to dimensional tolerance or the like, the transport space may have negative pressure to cause the fluid to generate bubbles. Specifically, when the fluid is a highly volatile liquid, vaporization causes generation of the bubbles, and when the fluid contains a large amount of dissolved gas, oversaturation causes generation of the bubbles. Once fluid generates bubbles, the fluid involves defectives in such usages as application and coating due to the bubbles.